1. Field Of The Invention
The present invention pertains to a motor driven rotary saw apparatus for earth trenching and rock or concrete cutting applications. The saw head is provided with a universal mounting structure for mounting the saw head on the end of an elongated boom supported on a transport undercarriage.
2. Background
In the art of rotary rock cutting and trenching saws there have been several developments in regard to saw mounting structure which provide for positioning the rotary saw head in a desired attitude for cutting trenches and performing other rock removal operations whereby the saw is traversed along a predetermined path. Although it has been previously accepted to provide a saw head which is mounted for movement about two mutually perpendicular axes with respect to a boom or other support structure, prior art types of supports have been limited with respect to the freedom of movement of the saw head to position it in the desired attitude. The prior art type of mounting structure thus requires a specialized undercarriage and support boom for the saw head in order to provide for the requisite degrees of freedom of movement of the head. Even so, the prior art specialized saw head support structure and previous attempts to modify conventional support structures, such as backhoe booms and the like, have not been satisfactory to provide the desired degree of freedom of orienting the saw blades. This is particularly a problem in trenching operations wherein the saw is cutting a trench to a depth requiring several passes of the saw by making successively deeper cuts with each pass and wherein the saw must be maintained aligned with the portions of the trench formed by previous cutting operations. Moreover, there are certain applications which can advantageously use a rotary rock saw which require positioning the saw adjacent to a vertical or inclined wall for milling operations to form a substantially smooth wall surface in a predetermined plane.
The requirement for improved saw head mounting structure has also dictated a need for controls for positioning the saw head and for allowing the saw head to follow a predetermined course in trench cutting operations, in particular.
Furthermore, there has also been a need for improvements in controls for providing a substantially constant energy input to the saw cutting or trenching operation to maximize the efficiency of the operation of the saw and its drive system. The improvements in the saw unit supporting structure provided by the present invention together with the improved control circuits for positioning and operating the saw in conjunction with traversal of the supporting undercarriage provide a somewhat synergistic effect in the art of hydraulically powered rotary trenching and rock cutting saw apparatus as will be recognized by those skilled in the art.